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04-13-2011, 03:18 AM   #1
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teleconverter

just bought a vivitar p/ka mount macro 1:1 2 x teleconverter.it does have contacts.will this make my 50mm manual lens a 50mm macro lens ?will it double my kit lenses 18mm- 55mm ,55mm -300mm ? is there any reason i would use it with my sigma 105 mm macro af or 100mm pentax manual focus macro lens. i have a k-x .thanks,scott

04-13-2011, 03:50 AM   #2
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QuoteOriginally posted by scottyboy Quote
just bought a vivitar p/ka mount macro 1:1 2 x teleconverter.it does have contacts.will this make my 50mm manual lens a 50mm macro lens ?will it double my kit lenses 18mm- 55mm ,55mm -300mm ? is there any reason i would use it with my sigma 105 mm macro af or 100mm pentax manual focus macro lens. i have a k-x .thanks,scott
Yes -it will double the effective focal length but I don't know what the image quality will be and I hope you will tell us when you test it!!

I'd be especially interested to know how well it works on the 55-300 at 300mm and 50mm close-up.

One way to test is to take a well focused photo of a detailed object with and without the tc. Enlarge the non-tc photo so the objects are the same size on the display. That's basically why one uses a TC; to get an enlarged image.
04-13-2011, 05:07 AM   #3
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I have played with one a while back and they work fairly well as an inexpensive option to macro. They will make your 50mm a 100mm macro lens as newart states, it doubles the effective focal lenght.
I'm not sure how they work with DA lense though. I believe you loose aperture control so this TC is best suited for lenses with aperture rings.
04-13-2011, 05:32 AM   #4
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QuoteOriginally posted by OrenMc Quote
<snip> I'm not sure how they work with DA lense though. I believe you loose aperture control so this TC is best suited for lenses with aperture rings.
If it's a P/K"A" mount like the OP said, it should be fine with aperture control on the more modern lenses (no autofocus or SDM of course)

04-13-2011, 06:02 AM   #5
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I stand corrected. Good to know, thanks
04-13-2011, 09:39 AM   #6
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as others have stated, it will double the focal length of any lens you have, BUT note, the lens will now become slower, since it will also change the maximum aperture.

for example, if you have a 50mmF2 it will become a 100mmF4 lens,

Of course, you will be in manual focus only, AND you will need to enter the focal length because the PK/A mount only has 6 data pins for aperture coding. The 7th pin for AF, and lens data is missing.

Additionally, depending on camera model, you can have metering errors, since the contacts are fed through the TC with no modification. This can lead to over exposure problems especially on the K10/20, if the origonal lens is faster than about F5.6. You should test and check this point.
04-13-2011, 10:58 AM   #7
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QuoteOriginally posted by newarts Quote
Yes -it will double the effective focal length but I don't know what the image quality will be and I hope you will tell us when you test it!!
This test talked me into buying one:

www.jr-worldwi.de: Photography

My thoughts: if you stick close to the intended use (a fast 50), you can get decent results. I played with other lenses and using it as a regular TC, even on a 400/5.6. It's not terrible but not great either.
04-13-2011, 12:51 PM   #8
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its in the mail ,i should have it by the weekend and as soon as i get time i will post some pics. using all lenes .i've only had camera for a few months and its my 1st slr/dslr .could be a learning experience.thanks for all the help,advice.scott


Last edited by scottyboy; 04-13-2011 at 12:56 PM.
04-13-2011, 01:23 PM   #9
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QuoteOriginally posted by Lowell Goudge Quote
as others have stated, it will double the focal length of any lens you have, BUT note, the lens will now become slower, since it will also change the maximum aperture.

for example, if you have a 50mmF2 it will become a 100mmF4 lens,

Of course, you will be in manual focus only, AND you will need to enter the focal length because the PK/A mount only has 6 data pins for aperture coding. The 7th pin for AF, and lens data is missing.

Additionally, depending on camera model, you can have metering errors, since the contacts are fed through the TC with no modification. This can lead to over exposure problems especially on the K10/20, if the origonal lens is faster than about F5.6. You should test and check this point.
i have a vivitar vmc 50mm 1:1.7 lens ,when setting the focal length do i set it at 50mm or 100mm when using adapter?
04-13-2011, 03:08 PM   #10
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scott

using the TC with any lens set focal length in camera to double the lens focal length. That is what a TC does.
04-16-2011, 01:30 PM   #11
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QuoteOriginally posted by newarts Quote
Yes -it will double the effective focal length but I don't know what the image quality will be and I hope you will tell us when you test it!!

I'd be especially interested to know how well it works on the 55-300 at 300mm and 50mm close-up.

One way to test is to take a well focused photo of a detailed object with and without the tc. Enlarge the non-tc photo so the objects are the same size on the display. That's basically why one uses a TC; to get an enlarged image.

hi ,here's some pics. with the 55-300 at 300 with and without the converter .its windy and cold today so i had to make it quick .also the bush is about 40 yards away, the robin about 40 feet .for being newbie and the weather i'm happy with results.i will get some macro later need to get ready to pick up girlfriend for dinner. i did nothing to the pics. straight from the camera.
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Last edited by scottyboy; 04-16-2011 at 01:35 PM.
04-16-2011, 02:21 PM   #12
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macro

newarts,heres a quater and a triple a batt. 50mm with macro conveter at 1:1. i might have missunderstood is this what you wanted or do you want a 50mm with conveter no macro closeup? snowglobe 50mm with tc. no macro about 2 1/2 feet away, globe about 6 inch dia.
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Last edited by scottyboy; 04-16-2011 at 02:43 PM.
04-17-2011, 10:46 AM   #13
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The Vivitar 2x Macro Focusing converter is meant to give a 1:1 image with a 50mm lens (resulting in 100mm 1:1). So if you set the converter to 1:1 and set your zoom to the 55mm, you'll be close to that. The best way to use it is to get your focus close, and then use Catch In Focus to get your shot.



Using longer focal lengths you can get closer photos.



More here.

Macro Test pictures by jjkyle - Photobucket

This was done at 120mm with the 50-135 on the converter.



Exif | K5JS4732_mDA50135_SiA_April13_2011 | Flickr - Photo Sharing!

This was done at 85mm



Exif | K5JS4699_mDA50135_SiA_April13_2011 | Flickr - Photo Sharing!


Last edited by JeffJS; 04-17-2011 at 11:01 AM.
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